Truing apparatus



'April 1 934 r E. SOBOLEWSKI 1,954,771

TRUING APPARATUS Original Filed April 23. 1921 5 Sheets-Sheet l I NVENTOR BY 3511,] ATTORNEY P 10,1934. E. SOBOLEWSKI 1 1,954,771

TRUING APPARATUS Original Filed April 23, 1921. 5 Sheets-Sheet 2 l NVENTOR ATTORNEY l 1934. E'. SOBOLEWSKI 1,954,771

TRUING APPARATUS Original Filed April 23. 1921 5 shgets-sheet 3 I NVENTOR BY v @0324 :5 ATTORNEY E. SOBOLEWSKI TRUING APPARATUS Ap ril 19, 1934.

1921 5 Sheets-Sheet 4 Original Filed April 23.

ATTORNEY A ril 10, 1934. E. SOBOLEWSKI TRUING APPARATUS Original Filed April 23, 1921 5 Sheets-Sheet 5 INVENTOR @1447, ATTORNEY Patented Apr. 10, 1934 PATENT OFFICE TRUING APPARATUS Edward Sobolewski, Cincinnati, Ohio, assignor to I Cincinnati Grinders Incorporated, a

tion of Ohio corpora Original application April 23, 1921, Serial No. 463,892. Divided and this application October 17, 1929, Serial No. 400,390 v 21 Claims. (Cl. 125-,11)

This invention relates to apparatus for truing or shaping wheels made of abrasive material.

One of the objects of this invention is to provide a truing apparatus of thoroughly rugged and practical construction, highly eificient action and well adapted to meet certain peculiar conditions met with in practical use. Another object of this invention is to provide a mechanism for rapidly and effectively preparing or shaping the grinding and regulating wheels of a grinding machine such as is disclosed in my parent application Serial No. 463,892, filed April 23, 1921, PatentNo. 1,733,086 and of which this application' is a division. In such apparatus the regulating wheel and the work which it positively rotates may be relatively inclined with respect to each other so as to cause the regulating wheel to efiect a feeding movement of the work in an axial direction; in such cases the regulating wheel, if it is to contact with the work in a straight line as it should, has a peculiar shape, and a further aim of this invention is to achieve the proper shaping of the regulating wheel, as well as of the grinding wheel, in such apparatus, and to achieve such shaping in a manner that can be quickly carried out and without requiring undue disturbance of the grinding apparatus itself and of the parts thereof. Another object is to provide a truing apparatus 01 the above character that\will be well adapted to meet the varying conditions of hard practical use. Other objects will bfetin part obvious or in part pointed out hereina er.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown a preferred embodiment of this invention.

Figure 1 is a right side elevation of the grinding apparatus in assembled relation, the lower portion of the apparatus being omitted;

Figure 2 is an elevation as seen from the left of Figure 1;

Figure 3- is a plan view on an enlarged scale of'the work-holding mechanism and certain of the control mechanism therefor, and of the wheel-truing mechanism;

Figure 4 is a vertical sectional view on an enlarged scale taken along the line 44 of Figure 3; Figure 5 is a vertical sectional view on an en- Figure 6 is a view, on an enlarged scale, as

seen partially from the rear of Figure 1 of the work-holding mechanism, wheel truing mechanism, certain of the control mechanism therefor, the frame of the machine being understood to be removed;

Figure 7 is a perspective view of one of the work-holding members which hold the work between the two wheels, and

Figure 8 is an elevation of part of the wheeltruing mechanism.

Similar reference characters refer to similar parts throughout the several views of the drawmgs.

Referring now to the drawings and more particularly to Figures 1 and 2, there is provided a main frame 1, having a suitable horizontally extending base, only a portion of which is shown in the drawings, and having an upper portion extending to the left; as viewed in Figure 1. In this upper over-hanging portion of the frame 1 there is supported in suitable bearings a spindle or arbor 2 carrying at one end thereof (the righthand end, as viewed in Figure 2) a grinding wheel 3 and carrying at the other end thereof (the lefthand end, as viewed in Figure 2) a pulley 4 over which runs the driving belt 5, connected to any suitable source of power, for driving the grinding wheel at a suitable grinding speed.

As will be clear from Figures 1 and 2, there is positioned. and rotatably supported underneath the grinding wheel 3 a wheel 7; one of the distinguishing features of the invention described and claimed in my parent application lies in the construction, relative arrangement, and drive of this wheel 7, and it may here be noted that the work A, interposed between the two wheels, will be seen to be physically supported on the wheel '7. The wheel 7 may be termed a work-supporting wheel, but in view of its primary function in controlling the rotation of the work A, all as hereinafter described in detail, I prefer to term it a work-rotating .or regulating wheel. The'wheel '7, preferably of abrasive material, is preferably of less diameter than the upper or grinding wheel 3 and in accordance with certain distinctive features of the invention, the regulating wheel 7 is made of sufficient length (axially, as viewed in Figure 2, and with respect to the width of the operative face of the grinding wheel 3) to support the work-A before, during, and after coming into contact with the grinding wheel 3. According to another distinctive feature of the invention, as hereinafter made clear, the wheel 7, because of this relative dimension with respect to the grinding wheel face, also rotates the work positively and uniformly and effects an axial feeding movement of the work before, during, and after the work is in contact with the grinding wheel 3. v

The wheel 7 is preferably so positioned that its axis (assuming its axis and the axis of the pe-- ripheral grinding wheel 3 to be parallel) and the axis of the grinding wheel 3 are in the same vertical plane; this preferred relation is clearly shown in Figure 1. The work-rotating wheel 7, however, is mounted so that its spindle 9, together with the wheel 7, may be swung out of parallelism with the axis of the grinding wheel and, more particularly, so that the axis of the work-rotating wheel 7 will be at an appropriate but relativelyv small angle to the axis" of the work A which is preferably held, by means more fully described below, so that the axis of the work A is substantially parallel to the axis of the peripherally operative grinding wheel 3. Preferably, also, the axes of the two wheels, where they operate by way of their peripheries, as is illustrated in the preferred embodiment shown in the drawings, are in horizontal planes. The above-described angular relation of the axis of the work-rotating wheel 7 to the axis of the work A achieves a feeding movement of the work A in an axial direction, as will be made more clear hereinafter.

Considering more in detail the mounting of the work-rotating wheel 7, it may first be noted that the base portion of the frame 1 has an upstanding hollow pedestal 10 (see Fig. 1) positioned substantially underneath the grinding wheel 3; the pedestal 10 is bored out to receive a cylindrical ram 11 having a table 12 formed at its upper portion. To the table 12 is secured a frame 42, the frame 42 being suitably formed to provide bearings 44 for rotatably supporting the spindle 9 which carries the wheel 7. A pulley 46 (Fig. 1) driven by a belt 47 (Fig. 2) from any suitable source of power drives the spindle 9 and the wheel 7 but through mechanism, generally indicated at 48 and controlled by hand wheel 59, whereby the wheel 7 is rotated comparatively slowly during the operation of the apparatus but at quite high speed while the wheel 7 is being dressed or trued.

The wheel 7 may be moved toward or away from the grinding wheel 3 by raising and lowering it, the ram 11 sliding vertically within the pedestal 10 under the control of hand wheel 25.

The upper end of the pedestal 10 is flanged,

. as at 14, and resting upon the upper face of the flange 14 is a collar 37 (Figs. 1 and 2) which is splined to the cylindrical ram 11, so that the collar 37 and ram 11 (the latter with the parts carried thereby) must turn together when swung about a vertical axis. The collar 37 is provided with arcuate slots 38, and passing through these slots are cap screws 39 for clamping the collar 3'7 to the pedestal 10. When it is desired to achieve an angular relation between the axis of the workrotating wheel 7 and the axis of the work A, in order to achieve an axial feeding movement of the work, the cap screws 39 are loosened up and the table 12, frame 42 carrying the wheel 7, and the ram 11, are turned about a vertical axis through the desired relatively small angle, all within the limited range permitted by the arcuate slots 38. The collar 37 of course turns with the ram 11 and, as indicated in Figure 1, the collar 37 may be provided with graduations to determine visually-the angular relation achieved between the axe Of the two wheels. In Figure 1 the graduations indicate a zero angle.

At the high or truing speed of rotation of the wheel 7, the latter may be dressed or trued. The ratio of the respective work-controlling and wheel-dressing speeds I prefer to be not less than 1 to 20 and not more than .1 to 50, but these ratios may be departed from, depending upon various factors met with in practice.

Considering now the manner in which the work pieces are held in operative relation to the grinding wheel 3 and the work-controlling wheel 7, it is first to be noted, referring to Figure 1, that the main frame 1 is provided with vertically extending guiding ways along which is vertically slidable a carriage 86 provided with a generally horizontally extending frame-like portion carrying two horizontally spaced work-holding members 109 which extend between the adjacent operative surfaces of the two wheels to form with the latter what may be termed a four-sided grinding throat. These parts will be described more fully hereinafter. A gib 87 (Fig. 3) secured to the carriage 86 by screws 88 coacts with the guides 80.

The vertical position of the carriage 86 along the ways 80, and hence the spacing of the workholding members 109 from the wheels, is determined bya suitable mechanism. The carriage 86 (Fig. 1) will be seen to have rotatably supported therein a screw 82 which passes through a nut 81 fixedly secured to the frai'ne 1. A suitablebearing 94 supports the'upper end of the screw 82, while keyed to the lower end thereof is a bevel gear 84 (Fig. 2). A bevel gear 92 meshes with the gear 84 and at its outer end has secured thereto a hand wheel 93. By manipulating the hand wheel 93 the screw 82 is rotated and the carriage 86 and the work-holding members 109 raised or lowered.

Extending to the left, as viewed in Figure 1, and to the right, as viewed in Figures 3 and 6, from the carriage 86 and preferably integrally formed therewith, is what may be termed a guide frame formed to provide two spaced guide members 95 and 96 (see Fig. 5) each reinforced, to

make it more rigid with respect to the carriage 86, by inclined bracing flanges 97. The grinding wheel 3 extends between the guide members 95 and 96, the latter being joined at their outer ends by a cross-piece 120 preferably formed integrally therewith. The upper faces and outer side faces of the members 95 and 96 are suitably machined to slidably receive the spaced carriages 98 and 113, one on each side of a line joining the axes of the two wheels (see Fig. 1).

Referring to Figure 5, the carriage 95 will be seen to rest against the under faces of the guide members 95 and 96 and is provided with the side portions 99 which have secured thereto, by the screws 102, the inwardly extending members 100 which overlap the laterally projecting portions of the guide members 95 and 96. The carriage 98 is thus slidable lengthwise of the members 95 and 96, and it may be adjustably positioned along the latter by means of a screw 104, operated bythe on each side of the boss 103, being fixed to the screw 104 to cause the carriage 98 to move with the screw when the latter moves axially as it is turned withrespect to the nut 107.

The carriage 98 carries a work-holding mem-,

her 109, preferably taking the form of a bar or plate-like member shown more clearly in Figure 7. The member 109 extendsunderneath and transversely of the spaced guiding members 95 and 96 (see Fig. 3) and is secured to the carriage" 98 by means ofcap screws 110 which pass through suitable recesses 111 (Fig. 7) in the ends of the member 109.

As shown in the drawings, one of the longitudinal edge faces of the member 109 is beveled,

and as is clear from Figure 1 of the drawings,-

A spondingly adjustably positioned, as will be clear from Figures 1 and 7.

The coacting work-holding member. 109, that is, the left-hand member 109, as seen in Figure 1, is secured in a similar manner to the carriage 113, the latter being of substantially similar construction to that of the carriage 93. The carriage 113 extends across the under faces of the guide members 95 and 96 (see Figs. 3 and 4) and has side portions 114 (Fig. 4) extending upward-' ly and exteriorly of the members 95 and 96, inwardly directed plate-like members 115, secured to the portions 114 by screws 102, overlapping the lateral projecting portions of the guide members 95 and 96. Thus, the carriage 113 is slidable lengthwise of the members 95 and 96.

The carriage 113 with the work-holding mem bers 109 carried thereby may be adjustably positioned by operating the hand wheel 118 (Figs. 1, 3 and 6) the hand wheel 118 actuates ascrew 117 which is threaded in a nut 119 carried by or formed in the cross-piece 120 which joins the ends of the guide members 95 and 96. The inner end of the screw 117 passes through a boss 116 (Figs. 3 and 6) on the carriage 113, collars 105 and 106, one on either side of the boss 116 and secured to the screw 117, causing the carriage 113 to move with the screw 117 as the latter moves longitudinallyduring its rotation relative to the nut 119.

The work-holding member 109 carried by the carriage 113 is of similar construction to that hereinabove described in connection with the carriage 98; as is clear from the drawings, Figure 1, for example, it also presents to the work A a surface that will be seen to be inclined.

In Figure 1 of the drawings the work-holding members 109 are shown in substantially the same horizontal plane and both above the center or axis of the work A. I wish to point out, however, thatthis is .a preferred relation of these parts with respect to the work and/or the wheels, but that the position thereof may be varied, if desired. For example, the two members 109- may be positioned in different planes as, for example, one may be offset vertically relative to the other. The end faces of the members 109 and which faces contact with the work preferably are shaped to be tangent to the latter, as well as inclined, as indicated in Figure 1, for, example, of the drawings. E

Considering'now briefly the operation of the apparatus, it is first to be noted that the grinding wheel 3, as above pointed out, is rotated at a suitable grinding speed; the lower wheel 7, which is to control the rotation of the work A and to cause axial feeding movement of the work, is drivenat-the relatively very slow speed achieved fwhenthfe hand ,whee159 is suitably set. The distance between the two wheels is predetermined by manipulating the hand wheel 25 to raise or lower the wheel 7 to an appropriate position with respect to the grinding wheel3. The carriage 86 is suitably positioned, by means of the hand wheel 93, in turn to position the work-holding members 109 appropriately with respect to the two wheels, preferably in substantially the relative position shown in Figure 1. The carriage 118 and 113, carried by the horizontal guides 95 and 96 of the carriage 86, are suitably adjusted along the guides '95 and 96, by means of the hand wheels 108 and 113, respectively, to space the work-holding members 109, carried by these carriages, appropriately relative to the d neter of the work A to be operated upon. thus, a four-sided grinding throat, made up by the grinding wheel 3, the

work-controlling wheelfl, and the two horizontally spaced work-holding 'members 109, is

preliminarily adjusted to receive the work to be operated upon. Where it is desired to cause the work A to move axially through the grinding throat, the work-controlling wheel 7 is swung about a. vertical axis to provide the desired relatively small feed angle between the direction of travel of the operative surface of the wheel 7 and the path of travel of the work A, as determined by the work-holding members 109. All of the above-mentioned adjustments have been described in detail hereinabove, but it might additionally be noted that the work-holding members 109 are so related that they hold the work A with the axis of the latter substantially parallel to the axis of the grinding wheel 3.

The two wheels, rotating at the respective speeds immediately above pointed out, are driven so that they rotate about their axes in the same direction, as viewed in Figure 1, for example. Thus, both wheels may be made to rotate in counter-clockwise direction, the operative surface of the grinding wheel where it contacts with the work A moving toward the right, and the operative surface of the regulating wheel 7, where it contacts with the work A, moving toward the left. During the operation of the apparatus, the grinding of the work A is substantially all done by the upper or grinding wheel 3, but by making the lower wheel, that is the wheel 7, of some hard material, like a relatively hard abrasive, the grip of the lower wheel on the work A insures proper rotation of the work relative to the grinding wheel 3 and, due to the angular relation above the work A.

As above pointed out and as is plainly shown in Figure 2 of the drawings, the operative surface of the regulating wheel 7 is of greater width than the adjacent operative surface of the grinding wheel 3; hence the lower wheel projects to either side of the grinding wheel 3, as the apparatus is viewed in Figure 2. The work pieces to be operated upon, assuming that the direction of feed by the regulating wheel 7 is in a direction from the right to the left, as viewed in Figure 2, are placed upon the right-hand projecting end portion of the wheel 7 and between the correspondingly projecting end portions of the workholding members 109, the weight of the work pieces A thus positioned being borne entirely by the wheel 7. Due to these relations of the parts,

the work pieces thus positioned are set into rotation by the wheel 7, any thrust on the work caused by the wheel 7 during this action being taken up by the left-hand work-holding member 109, as viewed in Figure 1; at the same time, due to the angular relation above-described, the wheel 7 causes the work, while it is thus being rotated, to move axially in a directionfrom the right to the left, as viewed in Figure 2. The weight of the work, being borne substantially entirely by the wheel '7, is effective, in conjunction with the low surface speed of the regulating wheel 7, to effect such an effective contact of the work with the regulating wheel 7 that the latter can readily insure proper rotation of the work prior to the entry of the work into contact with the grinding wheel 3. Thus, the grinding operation to be performed by the grinding wheel 3 commences upon an already properly rotating work piece.

The proper rotation of the work by the regulating wheel 7 continues as the latter feeds the work axially in a'direction from the right to the left, as viewed in Figure 2, until the work is moved to the left beyond the grinding wheel 3, whence the grinding operation is finished. The left-hand portions of the work-holding members 109, projecting to the left of the grinding wheel 3, as viewed in Figure 2, however, still act to hold the work upon and in operative contact with the regulating wheel '7 so that the latter can continue the rotation of the work and feed it away from the grinding wheel, whence it may be removed from the supporting wheel 7. Thus, rotation of the work continues therefore as and when the work moves out of operative .contact with the grinding wheel, so that marring or grinding of flats on the work is prevented.

' With both wheels rotating in the same direction, that is, in counter-clockwise direction, as m Figure 1, the adjacent operative surfaces of the two wheels,-and to which adjacent operative surfaces the work A is presented, travel in opposite directions with respect to a point intermediate thereof.

Considering certain further actions that take place in the operation of the apparatus, it might first here be noted that, when a work piece is placed upon the projecting portion of the regulating wheel 7, the weight of the work holds it down on the regulating wheel so that the latter, with its slowly moving surface, gets a grip on the work and starts the latter rotating. If the regulating wheel is tilted about the vertical axis of the column 11 (Fig. 8) so that there exists a proper feeding angle between the path of travel of the operative surfaceof the regulating wheel 7 and the path of travel in an axial direction of the work A (the path of travel of the work being determined by the work-holding members 109), the regulating wheel will also move the rotating work axially into contact with the grinding wheel and continue to rotate and feed the work even after the work passes out of contact with thegrinding wheel. Also, if any under-sized work is inserted into the apparatus, the undersized work will be rotated and fed and there is no danger of it being marred or touched by the grinding wheel, since the work iseifectively urged, by its weight, away from the grinding wheel and against the regulating wheel.

Anythrust on the work, caused by the movement of the operative surface of the regulating wheel 7 in a direction toward the left, as viewed in Figure 1, is taken up by the left-hand workholding member 109; this particular work-holding member 109 thus insures that the work A has its axis properly held with respect to the axis of the regulating wheel so that the feeding action of the wheel 7, while the work A is out of contact with the grinding wheel 3, may be. dependably carried on.

While the grinding wheel performs the grinding operation, there takes place a coactlon of one of the work-holding or supporting members 109 with the regulating wheel; if the wheels are roon the work A is taken up and has such an inclination that a component of the grinding wheel thrust is exerted in a direction to dependably urge the work toward or against the regulating wheel 7 and thus further insure effective contact between the surface of the regulating wheel and the work so that the former dependably controls the rotation and feed of the latter. Under certain conditions, also, this inclined surface of that work-holding member which takes up the thrust of the grinding wheel on the work is of great aid in bringing about speedily a true rounding-up of the work operated upon.

A water pipe 122 (see Figs. 3 and 1) is con nected to the cross-piece 120 (see also Fig. 4) the latter being provided with suitable passages 123 for guiding water to the point of contact between the grinding wheel and the work as the grinding wheel rotates in counter-clockwise direction, as viewed in Figure 1. A plate 124 (see Fig. 6) is positioned to catch and guide away water that is thrown off of the grinding wheel 3, the latter, in Figure 6, rotating in clockwise direction, theview of Figure 6 being from the rear of the apparatus as the latter is seen in Figure 1.

Because of the angular relation of the lower wheel 7 to the axis of the work when the wheel 7 is positioned to cause axial feeding movement of the work, the surface of the regulating wheel 7 which supports the work and which,.for accuracy of results, should support the work perfectly throughout its length, is necessarily a curve and this curve is substantially hyperbolic. For regulating wheel 7 is true to give it the desired curved surface so that it will present a straight line of contact to the work when it is adjusted to feed 3 and 6. The underside of the carriage 113 is provided with spaced lugs 130 (see Fig. 2) and these lugs support a shaft or rod 131 to the outer ends of which are secured the brackets 132 and 133 (see Figs. 2 and 3). Brackets 132 and 133 extend generally in a vertical plane and are preferably shaped, in side elevation, as is better shown in Figures 1 and 6, from which it will be seen that the brackets-are provided with arcuate slots 134, the center of curvature of which is coincident with the axis of the shaft or rod 131.

Screws 135 are threaded into the sides of the carriage 113 and pass through the arcuate slots 134 so that the arms or brackets 132 and 133 may be locked in whatever position they may beswung within the range permitted by the arcuate slots. During the normal operation of the apparatus, the brackets which, being attached to the rod 131, swing as a unit with the latter, are moved and held in their uppermost position, as is better shown'in Figure 1.

The ends of the arms or brackets 132 and 133 remote from the rod 131 are provided with S1117;- able openings; thus, a hole or opening in the outer end of the bracket 132 is adapted to receive a bushing 138,'while a similar hole or opening in the bracket or arm 133 receives the reduced end 143 of a sleeve 142, the latter being better shown in Figures 2 and 8. Setscrews 144 (Figure 3) serve to lock the bushing 138 and the sleeve 142 to their respective brackets.

are adapted to slidably guide a round rod 140 (see Fig. 3). The rod 140 carries a suitable cutting tool, such as a diamond 146, adapted, when drawn across the face of either of the two wheels, t turn 'the latter down, as the rod 140 is moved longitudinally with respect to itself, a knob 147 being provided to permit ease of manual sliding movement of the rod 140.

The sleeve 142, better shown in Figure 8 on an enlarged scale, is providedwith a straight slot 148 (see Figure 3) extending through its wall and substantially diametrically opposite this slot 148 there is formed in the sleeve a helical slot 150 (Fig. 8). A screw 145 threaded into the rod 140 is adapted to coact with either of these two slots,

When it is desired to dress or true the grinding wheel 3, the brackets 132 and 133 are swung downwardly from the position shown in Figure 1,

the sleeve 142 is secured in place in the bracket 133 with the straight slot 148 uppermost, as is shown in Figure 3, and the bushing 138 secured in place in the bracket 132. The rod 140 is then slid through the bushing 138 and into the sleeve 142, and the screw 145 passed through the slot 148 and threaded into a. suitable openingin the rod 140. The threaded opening in the rod 140 and the diamond 146 are so positioned or located that, when the screw 145 is assembled as abovedescribed, the diamond 146 will project upwardly from the rod 140, all as shown in Figure 3. The brackets 132 and 133 are then looked in position by means of the locking screws 135, it being noted that the rod 140 is thus positioned and held in parallelism with the axis of the grinding wheel 3.

The carriage 86 (see Figs. 1 and 6) is then elevated by manipulating the hand wheel 93 so as to raise the rod 140, with the diamond 146. thereon, to such a height that the rod 140 may be manually moved lengthwise of itself and the diamond 146 drawn across the face of the grinding wheel 3 to turn the latter down and dress it to its proper shape. During this sliding movement of the rod 140 the screw 145 (see Fig. 3) is guided by the straight slot 148 in the sleeve 142 so that thecutting point of the diamond 146 moves along a straight line. During this operation the grinding wheel 3 is, of course, rotated at a grinding speed.

If the regulating wheel '7 is set so that it exertsno feeding component upon the work A, and it is desired to true the wheel '7 to suit this condition, the set screw 144 (Fig. 3) is loosened up and the sleeve 142 rotated through 180 and again locked in position, the diamond 146 being now positioned on the underside-of the rod 140 and in position to operate upon the wheel '7. The carriage 86 is then lowered by manipulating the hand wheel 93 (Fig. 1) so as to bring the diamond 146 The central bores of the bushing 133 and of the sleeve 142 are aLned and to a suitable position for engaging and cutting the wheel '7 to the desired depth. The wheel '7 is driven at high speed during this truing operation, the speed-change mechanism shown in Figure 8 and hereinabove described in detail being adjusted or set to give the high truing speed. The diamond 146 is then drawn across the wheel '7 in a manner that will be clear from what'has been set forth above in regard to truing the grinding wheel 3.

If, however, the wheel '7 is to be set at an angle to give the desired or appropriate rateoi axial feeding movement to the work being operated upon, the sleeve 142, instead of being rotated tnrougn 180", as above described, is left in the position shown in Figure 3; the wheel '7 is left in the position for no feeding action and the screw 145 removed from the rod 140. The rod 140 is then rotated through 180 from the position shown in Figure 3, so that the diamond 146 now projects downwardly, and the threaded opening that receives the screw 145 also exposed downwardly. The screw 145 is then replaced, but this time through the helical slot 150 (see Fig. 8) As the diamond 146 is now moved across the face of the wheel '7, the latter running, of course, at a high or truing speed, the helical slot 150 causes a relatively slight swinging of the rod 140 about its axis in order thereby to vary or change the depth of out being taken by the diamond 146. The helical slot 150 is given a pitch proportional to the angle of feed whichit is desired to give the wheel '7 with respect to the axis of the work and through which angle the table 12 and the wheel 7 are to be swung in order to achieve a corresponding rate of feed. The wheel '7 is thus given the desired curvature-so that, when it is subsequently swung through the desired feed angle, it will present to the work a straight line of contact therewith.

During these truing operations the rod 140 may be moved back and forth longitudinally as often as is desired to give the wheels the desired smoothness of exposed surface. Of sourse, after the truing of the regulating wheel '7 has been accomplished, the speed-change mechanism is adjusted to a position such that the wheel '7 will be driven at the requisite low speed to efiect control of rotation'and control of feed of the work.

In order to facilitate adjusting of the wheels to receive therebetween a predetermined diameter of work, a graduated rod 153 (see Figs. 1, 3 and 6) is carried by one of the horizontally extending guide members 95, being preferably mounted in a boss 154 and being verticallyadjustable. A set screw 155 serves to look the graduated rod 153 in any desired position.

The rod 153 extends downwardly through the guide member and at its lower end is provided with a finger 156 extending transversely thereof and which may be swung inwardly to engage the face of the grinding wheel 3. The graduations way, test pieces may be put through the apparatus and final adjustments to achieve the intended diameter made by the mechanisms hereinabove described in detail.

Preferably the guide blades or work-holding members 109 are positioned so that their workcontacting' faces will hold the work with the axis of the latter parallel to the axis of the grinding wheel where the latter is operative by its peripheral or rim face.

It will thus be seen that there has been provided in this invention a truing apparatus in which the several objects and advantages hereinbefore noted, as well as many others, are successfully achieved. It will be noted that I am enabled to true the wheels without removing the -work-holding members 109, that the truing apparatus is readily moved into operative position in the grinding throat and may be readily swung out of the way or removed from the grinding throat. It will be seen that the apparatus is of thoroughly dependable construction and action of the grinding wheel and the peripheral face oi.

the thereto opposed regulating wheel of a centerless grinder in which the axis of the work rotated by the regulating wheel and the axis of the latter are inclined so as to cause the regulating wheel to feed the work in an axial direction, including, in combination, a rotatable member, means for guiding said member' between said opposed wheels and in a path substantially parallel to the axis of the grinding wheel, a truing tool carried by said member and displaced from the axis of rotation of the latter, means for preventing rotation of said member as it moves along with said truing tool extending in contact with the grinding wheel, and means for effecting a movement of said member about its axis as it is moved across the face of said regulating wheel and with said truing tool in contact with the latter.

2. An apparatus for truing the peripheral'face of the grinding wheel and the peripheral face of the thereto opposed regulating wheel ofa centerless grinder in which the axis of the work rotated by the regulating wheel and the axis of the latter are inclined so as to cause the regulating wheel to feedthe work in an axial direction, including, in combination, a rotatable member, means for guiding said member between said opposed wheels and in a path substantially parallel to the axis of the grinding wheel, a truing tool carried by said member and displaced from the axis of rotation of the'latter, and means for controlling the rotary movement of said member as thelatter is moved to traverse said truing tool across the face of said wheels, said means including a sleeve along which said member is movable, said sleeve having a straight slot for preventing rotary movement of said member when said truing tool is traversed by said member across thegrinding wheel face and a curved slot for causing-rotary movement of said memher as the latter traverses-said truing toolacross the face of said regulating wheel, said member having means adapted selectively to coact with either of said slots.

, 3. An apparatus for truing the peripheral face of the grinding wheeland the peripheral face of the thereto opposed regulating wheel of a centerless grinder in which the axis of the work rotated by the regulating wheel and the axis of the latter are inclined so as to cause the regulating Wheel to feed the work in an axial direc-- tion, including, in combination, a rotatable member, means for guiding said member between said opposed wheels and in a path substantially parallel to the axis of the grinding wheel, a truing tool carried by said member and displaced from the axis of rotation of the latter, and means for controlling the rotary movement of said member as the latter is moved to traverse said truing tool across the face of said wheels, said means including cam means having a straight portion and a curved portion, and means for causing said straight portion to prevent rotation of said member as the latter traverses said truing tool across the face of said grinding wheel, and means for causing said curved portion to effect rotary movement of said member as the latter traverses the truing tool across the face of said regulating wheel.

4. In apparatus of the character described, in combination, an abrasive wheel, a member having a substantially cylindrical outer surface, means mounting said member adjacent said abrasive wheel for turning about its own axis and for movement substantially lengthwise of its axis, a truing tool carried by said member and spaced from said axis, an arm projecting substantially radially from said member, and a pair of guiding edges between which said arm moves adapted to control the rotation of said member about its axis as said member moves lengthwise of its axis.

5. In apparatus of the character described, in combination, an abrasive wheel, a member having a substantially cylindrical outer surface, means mounting said member adjacent said abrasive wheel for turning about its own axis and for movement substantially lengthwise of its axis, a truing tool carried by said member and spaced from said axis, an arm projecting substantially radially from said member, means having a plurality of guiding edges, one of which is straight and another of which is curved, and along either of which said arm may be made to move to control .the rotation of said member about its axis as it moves lengthwise of its axis.

6. In apparatus of the character described, in

combination, an abrasive wheel, a member having a substantially cylindrical outer surface, means mounting said member adjacent said abrasive wheel for turning about its own axis and for movement substantially lengthwise of its axis, a truing tool carried by said member and spaced from said axis, an arm projecting sub- -a centerless grinder in and for movement substantially lengthwise of its axis, a truing tool carried by said member and spaced from said axis, an arm projecting substantially radially from said member, a sleeve along which said member moves, said sleeve having a plurality of slots extending in a direction generally lengthwise thereof and along any one of which said arm'may move as said member is moved lengthwise of its axis, said slots being of different shape.

8. In apparatus of the character described, in combination, an abrasive wheel, a member having a substantially cylindrical outer surface, means mounting said member adjacent said abrasive wheel for turning about its own axis and for movement substantially lengthwise of its axis, a truing tool carried by said member and spaced from said axis, an arm -projecting substantially radially from said member, a sleeve along which said member moves, said sleeve having a plurality of slots extending in a direction generally lengthwise thereof and along any one of which said arm may move as said member is moved lengthwise of its axis; said slots being of different shape, and means for effecting relative rotary displacement between said member and said sleeve for making any one of said slots effective.

9. In apparatus of the character described, in

combination, an abrasive wheel, a member hav ing a substantially cylindrical outer surface, means mounting said member adjacent said abrasive wheel for turning about ,its own axis and for movement substantially lengthwise of its axis, a truing tool carried by said member and spaced from said axis, an arm projecting substantially radially from said member, a sleeve along which said member moves, said sleeve having,a plurality of slots extending in a direction generally lengthwise thereof and along any one of which said arm may move as said member is moved lengthwise of its axis, said slots being of different shape, said arm being detachably secured to said member to permit its insertion into any one of said slots. 10. An apparatus for truing the peripheral face of the grinding wheel and the peripheral face of the thereto opposed regulating wheel of which the axis of the work rotated by the regulating wheel and the axis of the latter are inclined so as to cause the regulating wheel to feed the work in an axial direction, including, in combination, a rotatable member, means for guiding said member between said opposed wheels. and in a path substantially parallel to the axis of the grinding wheeL-a truing tool carried by said member and displaced from the axisof rotation of the latter, bearing means adapted to rotatably and slidably support said member, means mounting said bearing means to permit the latter to be swing into or out of a position to guide said member with the truing tool thereon across the face of said wheels, and means for controlling the rotary movement of said member about its axis as it moves lengthwise of its axis,

11. An apparatus for truing one of the wheels of a grinding apparatus having opposed abrasive wheels and two spaced work-holding means therebetween, including, in combination, a member carrying a truing tool, means for guiding said member in a path lengthwise of and between said spaced work-holding means and across the face of, one of said wheels, and means for movably mounting said guiding in combination, a

means and adapted to permit said guiding means to be positioned so as to cause said member to traverse said truing tool across the face of either of said two wheels.

12. An apparatus for truing one of the wheels of a grinding apparatus having opposed abrasive wheels and work-holding means therebetween, including, in combination, a member extending between the adjacent operative surfaces of said two wheels, said member carrying truing means, guiding means for said member, said guiding means providing a path of movement 'for said member in a direction lengthwise of said workholding means, and means pivotally mounting said guiding means adapted to'permit the latter to be swung toward either of said adjacent operative surfaces of said two wheels.

13. An apparatus for truing one of the wheels of a grinding apparatus which has opposed abrasive wheels and two spaced work-holding devices forming a four-sided grinding throat including, in combination, a member carrying a truing tool, said member being of dimensions to permit it to pass through said four-sided grinding throat, and guiding means for said member for, guiding the latter through the space between the parts forming the grinding throat and in such a path that movement of said member through said grinding throat traverses said truing tool across the face of one of said wheels, whereby truing is achieved without removing any of the parts of said'grinding throat.

14. An apparatus for truing one of the wheels of a grinding apparatus which has opposed abrasive wheels and two spaced work-holding devices forming a four-sided grinding throat including, member carrying a truing tool, said member being of dimensions to permit it to pass through said four-sided grinding throat, and a pair of spaced guiding means, each substantially at one end of said grinding throat for guiding said member in its movement through said grinding throat, whereby truing is achieved without removing any of the parts of said grinding throat.

15. An apparatus for truing one of the wheels of a grinding apparatus which has opposed abrasive wheels and two spaced work-holding devices forming a four-sided grinding throat including, in combination, a member carrying a truing tool, said member being of dimensions to permit it to pass through said four-sided grinding throat, a pair of spaced guiding means, each substantially at one end of said grinding throat for guiding said member in its movement through said grinding throat, whereby truing is achieved without removing any of the parts of said grinding throat, and means mounting said two guiding means for movement into guiding position and for movement out of grinding-throat-obstructing position.

16. In apparatus of the character described, in combination, a grinding wheel, a regulating wheel, a work-holding member extending between said wheels and adapted-to take up the thrust of the grinding wheel on the work, supporting means for holding said-work-holding member in position, a member carrying a truing tool, means for guiding said member so that said truing tool is traversed across the face of one, of said wheels, and means mounting said guiding means on said supporting means, said mounting means being constructed so that said guiding means is movable relative to said supporting of the working range of said two wheels and work-holding member.

17. In apparatus of the character described, in combination, a grinding wheel, a regulating wheel, a work-holding member extending between said wheels and adapted 'to take up the thrust of the grinding wheel on the work, a pair of spaced members, one on each side of said wheels, for holding said work-holding means in position, a member carrying a truning tool, and a pair of guiding devices, each supported by one of said spaced members, for guiding said member in its movement across the face of one of said wheels.

18. In apparatus of the character described, a grinding wheel, a regulating member extending beof said wheels, for holding said work-holding means in position, a member carrying a truing tool, a pair of guiding devices, each supported by one of said member from possible obstruction.-

T9. In apparatus of the character described, in bination, a grinding wheel, a regulating a reel, a work-holding member extending between said wheels and adapted to take up the thrust the grinding wheel on the work, a pair of spaced members, one on each side of the wheel for holding said work-holding means in position, a truing tool,

20. An'apparatus for truing the peripheral face of the grinding wheel and the peripheral face of the' thereto opposed regulating wheel of a centerless grinder in which the axis of the work rotated by the regulating wheel and the axis of the latter are inclined so as to cause the regulating wheel to feed the work in an axial direction, including, in combination, a rotatable member extending between the opposed faces of said wheels, means for guiding said member in a direction substantially lengthwise of its axis and in a path between said opposed faces of said wheels, 2. truing tool carried by said member and displaced from the axis of rotation of the latter, said guiding means including bearing means in which said rotatable member is rotatably mounted, means operating during lengthwise movement of said rotatable member along said path for efiecting rotary movement'of said member about its axis and hence for truing tool as the latter is traversed across a wheel face, and means for movably mounting or out of a posit her with the truing tool thereon across a wheel face.

21. An apparatus for truing-one of the wheels J a path lengthwise of said work-holding means,

said guiding means having bearing means in which said member is rotatably supported, means for eifecting moveme t of said member about its axis as, it is moved along the path determined by of a position to guide said member with the truing' means thereon across the face of a wheel.

EDWARD SOBOLEWSKI.

eiiecting rotary movement of said 

